Update test information in readme

Author: zbarbuto

README.md

@@ -350,9 +350,13 @@ Destroying models may result in errors due to foreign key integrity. First delet
 
 ## Running tests
 
-The tests in this repository are mainly integration tests, meaning you will need
-to run them using our preconfigured test server.
+You will need a postgres database created locally and a user with full read/write access to the database (substitute as required with values appropriate to your setup):
+
+1. `CI=true PGHOST=localhost PGPORT=<pgport> PGDATABASE=<dbname> PGUSER=<username> PGPASSWORD=<password> npm test`
+
+The defaults are:
+
+Host | Port | Database | User | Password
+--- | --- | --- | --- | ----
+localhost | 5432 | emptytest | test | _none_
 
-1. Ask a core developer for instructions on how to set up test server
-   credentials on your machine
-2. `npm test`